1. Field of Invention
The present invention relates to a biological electrode, and more particularly to a biological electrode which is suitably used for the bioelectrical monitoring and/or bioelectrical stimulation by disposing an electrode element capable of having electroconductivity with a living body at a predetermined position.
2. Related Art
Conventionally, for the bioelectrical monitoring and/or bioelectrical stimulation for the medical and/or biological purposes, the measurement was conducted by attaching a biological electrode at a predetermined position of a living body.
The biological electrodes are roughly classified into a disposable type and a re-usable type.
A re-usable biological electrode is durable, and thus rarely wasted, with less risk of bringing about a significant waste problem.
In recent years, a disposable biological electrode has been more and more used to avoid infection. Since a large quantity of disposable biological electrodes are used and wasted, and the material that is less degradable in the natural environment is employed, there is a risk of causing a waste problem such as insufficient garbage dump.
The conventional structure of an electrode element for use with the disposable biological electrode can be roughly classified into two types as follows.
The first type is a so-called snap fastener type in which the electrode element is connected via a snap connector to the lead wire.
The second type is a so-called film element type in which the electrode element is like a film, with its one end being connected via an alligator clip to the lead wire, for example.
In FIG. 6, a biological electrode 41 comprises a snap fastener type element 42, an adhesive tape 43, a gel sponge 44, and an electrode paste 45 or the like, and is used as a disposable electrode for the electrocardiogram monitor, for example.
Conventionally, as the material of the disposable biological electrode 41, ABS resin (acrylonitrile butadiene styrene copolymer) was employed for the snap fastener type electrode element 42. The electrode element 42 is made electroconductive by kneading an electroconductive filler such as carbon into ABS resin or by coating an electroconducitve paint on its surface to form an electroconductive layer. Also, a non-polarized electroconductive paint such as silver/silver chloride paint is coated on the contact face of the electrode paste 45 on the electrode element 42, as required, to give a stable performance to the electrode element 42 of the biological electrode 41.
Further, the contact between the electrode element 42 and a connecting terminal of the electrode lead wire is improved by coating a highly electroconducitve paint on a lead wire attaching portion of the electrode element 42, or by putting a stainless cover (e.g., a stud) thereon.
On the other hand, a biological electrode 50 of film element type has an electroconductive layer 53 that is formed by coating an electroconducitve paint such as silver/silver chloride paint on at least a part of one face of a substrate 52 made of PET resin (polyethylene terephthalate) or the like, and an electroconductive gel 54 fixedly provided with the electroconductive layer 53, as shown in FIG. 7. And the biological electrode 50 is employed as a disposable electrode for electrocardiography, for example.
A large quantity of disposable biological electrodes are used for the purposes of the electrode for electrocardiogram monitoring in the ward, or the tab electrode for group medical checkup making use of the electroconductive adhesive gel, and also wasted.
Of the materials used in the biological electrode 41 as shown in FIG. 6, the electrode element 42 in particular is made of ABS resin, and in an embodiment as shown in FIG. 7, the substrate 52 in particular is made of PET resin. Therefore, in an incinerating process, a large amount of heat is generated while incinerating, whereby there is a drawback that an incinerator is easily damaged.
In the garbage dump after the use, the noncombustible waste is less liable to degrade in the natural environment, when wasted, and remains in the environment over the long term without degrading in the soil. Therefore, it is apprehended that the lifetime of the garbage dump or final repository site may be shortened, thereby causing some load on the natural environment.
The present invention has been achieved in the light of the above-mentioned problems, and it is an object of the invention to provide a biological electrode that causes less natural environmental load, even if wasted in large quantities in the soil, or generates a small heat amount while incinerating, not damaging the incinerator.
The first invention provides a biological electrode comprising at least an electrode element capable of having electroconductivity with a living body, the biological electrode being used by disposing the electrode element at a predetermined position, wherein a biodegradable material is used in the electrode element of the biological electrode.
Accordingly, according to the invention, the use of a biodegradable material for the biological electrode can not only retain the electrochemical performance and mechanical performance, but also can be degradable into the water and carbon dioxide ultimately owing to microbes, when wasted in the soil.
In the incineration process, the biological electrode of the invention generates a smaller amount of heat while incinerating than the conventional electrode made of ABS resin or PET resin.
The second invention provides the biological electrode, wherein the biodegradable material contains a material selected from at least one of cellulose, polyhydroxy carboxylic acids, chitosan, aliphatic polyester (e.g., polybutylenesuccinate (PBS), polybutylenesuccinate adipate (PBSA), polyethylenesuccinate (PESu)), polycaprolactone (PCL), and starch derivatives. Therefore, the biological electrode of the invention is degradable into the water and carbon dioxide ultimately owing to microbes, and generates a small amount of heat while incinerating in the incineration process.
The third invention provides the biological electrode, wherein an electroconductive filler is specifically added to a matrix of the electrode element to afford the electroconductivity.
The fourth invention provides the biological electrode, wherein an electroconductive layer is specifically formed on the surface of a matrix or substrate of the electrode element to afford the electroconductivity.
The fifth invention provides the biological electrode, wherein the substrate is a non-woven fabric made of the biodegradable material. The substrate composed of the non-woven fabric is so flexible as to reduce delamination or uncomfortableness in attaching, with excellent air permeability, and has the functions of low heat generation while incinerating and degradation in the soil with the garbage disposal after the use.
The sixth invention provides the biological electrode, further comprising a pad portion which is a non-woven fabric made of the biodegradable material. The pad portion composed of the non-woven fabric is so flexible as to reduce delamination or uncomfortableness in attaching, with excellent air permeability, and has the functions of low heat generation while incinerating and degradation in the soil with the garbage disposal after the use.
The seventh invention provides the biological electrode, wherein the biodegradable materials contains a material selected from at least one of cellulose, polyhydroxy carboxylic acids, chitosan, aliphatic polyester (e.g., polybutylenesuccinate (PBS), polybutylenesuccinate adipate (PBSA), polyethylenesuccinate (PESu)), polycaprolactone (PCL), and starch derivatives. Thereby, it is possible to have the superior functions of low heat generation while incinerating and degradation in the soil.
The eighth invention provides the biological electrode, wherein the biodegradable material is used for all the constituent members of the biological electrode.
The ninth invention provides a method of manufacturing an electrode element of a biological electrode, characterized by including a step of kneading a biodegradable material as a matrix and an electroconductive filler, and a step of injection molding after kneading.
The tenth invention provides a method of manufacturing an electrode element of a biological electrode, characterized by including a step of coating or infiltrating an electroconductive paint on a film or a non-woven fabric made of a biodegradable material as a substrate.